1. Field of the Invention
Automatic drafting instruments of the type supporting one or more tubular writing pens in either a lowered writing position with the pen tip contacting the writing surface or an upper rest position with the pen tip out of contact with the writing surface. A problem encountered in such mechanisms is drying of ink within the pen tip when the tubular writing pen is in the retracted or rest mode. As a result of the drying ink, such a pen when returned to the lowered writing mode will draft irregular lines during initial operation.
2. Description of the Prior Art
Accordingly, it has been an object of the prior art to provide automatic drafting devices with means which will prevent drying out of ink within tubular writing pens.